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2.法线向量将顶点着色器的法线信息接收，并进行标准化
1vec3 uNormal=normalize(Normal);

3.片元到摄像头的位置,"> 
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        <h1 class="title">OpenGL学习之路之光源大总结</h1>
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            <span>十二月 19, 2021</span>
            
  <ul class="post-tags-list" itemprop="keywords"><li class="post-tags-list-item"><a class="post-tags-list-link" href="/blog/tags/OpenGL/" rel="tag">OpenGL</a></li></ul>


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            <h1 id="光源所需条件"><a href="#光源所需条件" class="headerlink" title="光源所需条件"></a>光源所需条件</h1><h4 id="1-光照信息"><a href="#1-光照信息" class="headerlink" title="1.光照信息"></a>1.光照信息</h4><p>定向光 点光源 聚光灯的属性</p>
<h4 id="2-法线向量"><a href="#2-法线向量" class="headerlink" title="2.法线向量"></a>2.法线向量</h4><p>将顶点着色器的法线信息接收，并进行标准化</p>
<figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">vec3 uNormal=<span class="built_in">normalize</span>(Normal);</span><br></pre></td></tr></table></figure>

<h4 id="3-片元到摄像头的位置"><a href="#3-片元到摄像头的位置" class="headerlink" title="3.片元到摄像头的位置"></a>3.片元到摄像头的位置</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">vec3 dirToCamera=<span class="built_in">normalize</span>(cameraPos-FragPos);</span><br></pre></td></tr></table></figure>

<h2 id="定向光"><a href="#定向光" class="headerlink" title="定向光"></a>定向光</h2><h4 id="主要光照信息"><a href="#主要光照信息" class="headerlink" title="主要光照信息"></a>主要光照信息</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">struct</span> <span class="title class_">LightDirectional</span>&#123;</span><br><span class="line">  vec3 pos;<span class="comment">//光源坐标</span></span><br><span class="line">  vec3 color;<span class="comment">//光颜色</span></span><br><span class="line">  vec3 dirToLight;<span class="comment">//光照角度</span></span><br><span class="line">&#125;;</span><br></pre></td></tr></table></figure>

<h4 id="特点"><a href="#特点" class="headerlink" title="特点"></a>特点</h4><p>不需要光照衰弱，光照与位置无关</p>
<h4 id="diffuse"><a href="#diffuse" class="headerlink" title="diffuse"></a>diffuse</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">diffuseIntersity=<span class="built_in">max</span>(<span class="built_in">dot</span>(light.dirToLight,Normal),<span class="number">0</span>);</span><br><span class="line">diffuse=diffuseIntersity*light.color*<span class="built_in">texture</span>(material.diffuse,TexCoord).rgb;</span><br></pre></td></tr></table></figure>

<h4 id="specular"><a href="#specular" class="headerlink" title="specular"></a>specular</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">specularIntersity=<span class="built_in">pow</span>(<span class="built_in">max</span>(<span class="built_in">dot</span>(<span class="built_in">normalize</span>(<span class="built_in">reflect</span>(-light.dirToLight,Normal)),dirToCamera),<span class="number">0</span>),material.shininess);</span><br><span class="line">vec3 specular=specularIntersity*light.color*<span class="built_in">texture</span>(material.specular,TexCoord).rgb;</span><br></pre></td></tr></table></figure>

<h2 id="点光源"><a href="#点光源" class="headerlink" title="点光源"></a>点光源</h2><h4 id="主要光照信息-1"><a href="#主要光照信息-1" class="headerlink" title="主要光照信息"></a>主要光照信息</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">struct</span> <span class="title class_">LightPoint</span>&#123;</span><br><span class="line">  vec3 pos;</span><br><span class="line">  vec3 color;</span><br><span class="line">  vec3 dirToLight;<span class="comment">//用不上</span></span><br><span class="line">    <span class="type">float</span> constant;<span class="comment">//1.0f</span></span><br><span class="line">    <span class="type">float</span> linear;<span class="comment">//0.09f</span></span><br><span class="line">    <span class="type">float</span> quadratic;<span class="comment">//0.032f</span></span><br><span class="line">&#125;;</span><br></pre></td></tr></table></figure>

<h4 id="特点-1"><a href="#特点-1" class="headerlink" title="特点"></a>特点</h4><p>与光照方向无关</p>
<h4 id="attenuation"><a href="#attenuation" class="headerlink" title="attenuation"></a>attenuation</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line"><span class="type">float</span> distantes=<span class="built_in">length</span>(light.pos-FragPos);</span><br><span class="line"><span class="type">float</span> attenuation=<span class="number">1.0f</span>/light.constant+light.linear*distantes+light.quadratic*distantes*distantes;</span><br></pre></td></tr></table></figure>



<h4 id="diffuse-1"><a href="#diffuse-1" class="headerlink" title="diffuse"></a>diffuse</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">diffuseInyersity=<span class="built_in">max</span>(<span class="built_in">dot</span>(<span class="built_in">normalize</span>(light.pos-FragPos),Normal),<span class="number">0</span>);</span><br><span class="line">vec3 diffuse=diffuseIntensity*<span class="built_in">texture</span>(material.diffuse,TexCoord).rgb*light.color;</span><br></pre></td></tr></table></figure>

<h4 id="specular-1"><a href="#specular-1" class="headerlink" title="specular"></a>specular</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line"><span class="type">float</span> specularIntersity=<span class="built_in">pow</span>(<span class="built_in">max</span>(<span class="built_in">dot</span>(<span class="built_in">normalize</span>(<span class="built_in">reflect</span>(-<span class="built_in">normalize</span>(light.pos-FragPos),uNormal)),dirToCamera),<span class="number">0</span>),material.shininess);</span><br><span class="line">  vec3 specular=specularIntersity*light.color*<span class="built_in">texture</span>(material.specular,TexCoord).rgb;</span><br></pre></td></tr></table></figure>

<h2 id="聚光灯"><a href="#聚光灯" class="headerlink" title="聚光灯"></a>聚光灯</h2><h4 id="主要光照信息-2"><a href="#主要光照信息-2" class="headerlink" title="主要光照信息"></a>主要光照信息</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">struct</span> <span class="title class_">LightSpot</span>&#123;</span><br><span class="line">  vec3 pos;</span><br><span class="line">  vec3 color;</span><br><span class="line">  vec3 dirToLight;<span class="comment">//有用</span></span><br><span class="line">    <span class="type">float</span> constant;</span><br><span class="line">    <span class="type">float</span> linear;</span><br><span class="line">    <span class="type">float</span> quadratic;</span><br><span class="line">  <span class="type">float</span> cosPhyInner;</span><br><span class="line">  <span class="type">float</span> cosPhyOutter;</span><br><span class="line">&#125;;</span><br></pre></td></tr></table></figure>

<h4 id="特点-2"><a href="#特点-2" class="headerlink" title="特点"></a>特点</h4><p>边缘模糊化，对比点光源需要会受角度影响</p>
<h4 id="代码"><a href="#代码" class="headerlink" title="代码"></a>代码</h4><figure class="highlight c++"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br></pre></td><td class="code"><pre><span class="line">vec3 result=<span class="built_in">vec3</span>(<span class="number">0</span>,<span class="number">0</span>,<span class="number">0</span>);</span><br><span class="line"><span class="comment">//attenuation</span></span><br><span class="line"><span class="type">float</span> distances= <span class="built_in">length</span>(light.pos - FragPos);</span><br><span class="line"><span class="type">float</span> attenuation=<span class="number">1.0f</span>/(light.constant+light.linear*distances+light.quadratic*distances*distances);</span><br><span class="line"><span class="type">float</span> spotRatio=<span class="number">0</span>;</span><br><span class="line"><span class="type">float</span> cosTheta=<span class="built_in">dot</span>(<span class="built_in">normalize</span>(FragPos-light.pos),<span class="number">-1.0f</span>*light.dirToLight);</span><br><span class="line"><span class="comment">//cosTheta=1;</span></span><br><span class="line"><span class="keyword">if</span>(cosTheta &gt; light.cosPhyInner)</span><br><span class="line">&#123;</span><br><span class="line">  spotRatio=<span class="number">1.0f</span>;</span><br><span class="line">&#125;<span class="keyword">else</span> <span class="keyword">if</span>(cosTheta &gt; light.cosPhyOutter)&#123;</span><br><span class="line">  <span class="comment">//spotRatio=1.0f-(cosTheta-light.cosPhyInner)/(light.cosPhyOutter-light.cosPhyInner);</span></span><br><span class="line">  spotRatio=(light.cosPhyOutter-cosTheta)/(light.cosPhyOutter - light.cosPhyInner);</span><br><span class="line">&#125;</span><br><span class="line"><span class="keyword">else</span>&#123;</span><br><span class="line">  spotRatio=<span class="number">0.0f</span>;</span><br><span class="line">&#125;</span><br><span class="line">attenuation*=spotRatio;</span><br><span class="line"><span class="comment">//diffuse</span></span><br><span class="line"><span class="type">float</span> diffuseIntensity=<span class="built_in">max</span>(<span class="built_in">dot</span>(<span class="built_in">normalize</span>(light.pos-FragPos),uNormal),<span class="number">0</span>);</span><br><span class="line">vec3 diffuse=<span class="built_in">texture</span>(material.diffuse,TexCoord).rgb*light.color*diffuseIntensity;</span><br><span class="line">result+=diffuse;</span><br><span class="line"></span><br><span class="line"><span class="comment">//specular</span></span><br><span class="line"><span class="type">float</span> specularIntersity=<span class="built_in">pow</span>(<span class="built_in">max</span>(<span class="built_in">dot</span>(<span class="built_in">normalize</span>(<span class="built_in">reflect</span>(-<span class="built_in">normalize</span>(light.pos-FragPos),uNormal)),dirToCamera),<span class="number">0</span>),material.shininess);</span><br><span class="line">vec3 specular = specularIntersity*<span class="built_in">texture</span>(material.specular,TexCoord).rgb*light.color;</span><br><span class="line">result+=specular;</span><br><span class="line"><span class="comment">//result*=attenuation;</span></span><br><span class="line">result*=spotRatio;</span><br><span class="line"><span class="keyword">return</span> result;</span><br></pre></td></tr></table></figure>




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			<ol class="toc"><li class="toc-item toc-level-1"><a class="toc-link" href="#%E5%85%89%E6%BA%90%E6%89%80%E9%9C%80%E6%9D%A1%E4%BB%B6"><span class="toc-number">1.</span> <span class="toc-text">光源所需条件</span></a><ol class="toc-child"><li class="toc-item toc-level-4"><a class="toc-link" href="#1-%E5%85%89%E7%85%A7%E4%BF%A1%E6%81%AF"><span class="toc-number">1.0.0.1.</span> <span class="toc-text">1.光照信息</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#2-%E6%B3%95%E7%BA%BF%E5%90%91%E9%87%8F"><span class="toc-number">1.0.0.2.</span> <span class="toc-text">2.法线向量</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#3-%E7%89%87%E5%85%83%E5%88%B0%E6%91%84%E5%83%8F%E5%A4%B4%E7%9A%84%E4%BD%8D%E7%BD%AE"><span class="toc-number">1.0.0.3.</span> <span class="toc-text">3.片元到摄像头的位置</span></a></li></ol></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#%E5%AE%9A%E5%90%91%E5%85%89"><span class="toc-number">1.1.</span> <span class="toc-text">定向光</span></a><ol class="toc-child"><li class="toc-item toc-level-4"><a class="toc-link" href="#%E4%B8%BB%E8%A6%81%E5%85%89%E7%85%A7%E4%BF%A1%E6%81%AF"><span class="toc-number">1.1.0.1.</span> <span class="toc-text">主要光照信息</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#%E7%89%B9%E7%82%B9"><span class="toc-number">1.1.0.2.</span> <span class="toc-text">特点</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#diffuse"><span class="toc-number">1.1.0.3.</span> <span class="toc-text">diffuse</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#specular"><span class="toc-number">1.1.0.4.</span> <span class="toc-text">specular</span></a></li></ol></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#%E7%82%B9%E5%85%89%E6%BA%90"><span class="toc-number">1.2.</span> <span class="toc-text">点光源</span></a><ol class="toc-child"><li class="toc-item toc-level-4"><a class="toc-link" href="#%E4%B8%BB%E8%A6%81%E5%85%89%E7%85%A7%E4%BF%A1%E6%81%AF-1"><span class="toc-number">1.2.0.1.</span> <span class="toc-text">主要光照信息</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#%E7%89%B9%E7%82%B9-1"><span class="toc-number">1.2.0.2.</span> <span class="toc-text">特点</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#attenuation"><span class="toc-number">1.2.0.3.</span> <span class="toc-text">attenuation</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#diffuse-1"><span class="toc-number">1.2.0.4.</span> <span class="toc-text">diffuse</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#specular-1"><span class="toc-number">1.2.0.5.</span> <span class="toc-text">specular</span></a></li></ol></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#%E8%81%9A%E5%85%89%E7%81%AF"><span class="toc-number">1.3.</span> <span class="toc-text">聚光灯</span></a><ol class="toc-child"><li class="toc-item toc-level-4"><a class="toc-link" href="#%E4%B8%BB%E8%A6%81%E5%85%89%E7%85%A7%E4%BF%A1%E6%81%AF-2"><span class="toc-number">1.3.0.1.</span> <span class="toc-text">主要光照信息</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#%E7%89%B9%E7%82%B9-2"><span class="toc-number">1.3.0.2.</span> <span class="toc-text">特点</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#%E4%BB%A3%E7%A0%81"><span class="toc-number">1.3.0.3.</span> <span class="toc-text">代码</span></a></li></ol></li></ol></li></ol></li></ol>	
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